Rail heating device



Feb. 19, 1935. w H GREENHELD 1,991,801

RAIL HEATING DEVICE Filed Oct. 7, 1930 2 Sheets-Sheet l fu enior WILLIAMH.GREENFIELD Feb. 19,, 1935- w. H. GREENFIELD RAIL HEATING DEVICE FiledOct. 7. 1930 2 Sheets-Sheet 2 WILLIAM H.GREENFIELD Patented Feb. 19,1935 UNITED STATES PATENT OFFICE 1 1 Claim.

, This invention relates to rail heating devices and more particularlyto electric heaters which are operative to prevent the formation oraccumulation of sleet, snow and ice around rail switches and derailpoints and on conductor rails employed on electrified railroads todeliver power to cars or trains. Primarily the invention consists ofheat radiating units positioned at said switch or derail points or atintervals spaced along said conductor rails for supplying heat to thetrack, these units being electrically operated from local or distantstations as may be desired.

It is among the principal objects of the present invention to providemeans for applying heat to predetermined zones of a railway track bydirect radiation from a high resistance heating element, this elementbeing in the form of an electric resistor which is adapted to raise thetemperature of the rail in the zone in which the element is located to adegree sufficiently high to prevent the formation of sleet, snow or icein said zone. 1

A further object of the invention is to provide a housing or casing forthe resistance element which is so designed as to effectivelyconcentrate the heat in the desired zone whereby the loss in heattransmission from said element to the rail is reduced to a veritableminimum. 1

Still another object of the invention is the pro visionof a casing whichis operative not only to resist the radiation of heat outwardly from therail but which is also designed to support the resistor element againstinjury due to the vibration and shocks to which it is ordinarilysubjected while in use.

A still further object of the invention is the provision of means formedintegrally in the re-.

sistor housing for commonly encasing the end terminals of the resistorsand the corresponding encasing means being so designed as to greatlyfacilitate the quick-detachable connection of said conductors with theheating unit.

Still another and important object of the invention is the provision ofspring-pressed means for quick-detachably securing the heating unit inoperative'position against the rail, said securing means being of suchcharacter as to entirely eliminate the necessity for screw or bolt holesin the rail.

Other objects of the invention, such as those relating generally tosimplicity in design, economies of manufacture and efficiency anddurability in use and specifically todetails of construction will appearmore fully hereinafter.

terminals of the conductors leading thereto, these The inventionconsists substantially in the combination, construction, location andrelative arrangement of parts, all as will be described more fullyhereinafter, as'shown in the accompanying drawings and as finallypointed out in the ap- -5 pended claim. In the accompanying drawingswherein have been illustrated preferred embodiments of the invention:-

Figure 1 is an elevational view of a rail equipped with a heating unitconstructed in accordance with and embodying the principles of thepresent invention; 1

Figure 2 is a cross sectional view taken on the line 22 of Figure 1; v

Figure 3 is a vertical cross sectional view of the heater unit per setaken on the line 33 of Figure 1;

Figure 4 is a partial transverse cross sectiona view taken on the line44 of Figure 3;

Figure 5 is a perspective view showing the interior of the unit;

Figure 6 is an exterior perspective view of the unit;

Figure 7 is a perspective view of the conductor plug retaining plate;

Figure 8 is a longitudinal sectional view of one form of resistanceelement;

Figure 9 is a cross sectional view taken on the line 9-9 of Figure 8;

Figure 10 is a longitudinal sectional view of a modified form ofresistance element;

1 Figure 11 is a cross sectional View taken on line 11-11 of Figure 10;

Figures 12 and 14 are plan views respectively of different forms ofspring clamps for retaining the heater unit in position; and

Figures 13 and 15 are sectional views taken respectively on line 13--13of Figure 12 and line 1515 of Figure 14.

Referring now to the drawings and more particularly to Figures 1 to 6thereof, it will be observed that the rail heating unit, designatedgenerally by the reference numeral 10, is adapted to be mounted inposition within the angle formed between the base flange and web of amain rail R. It will be understood that this rail 11 may be a portion ofan ordinary track switch or frog or a portion of a conductor rail forsupplying electric power to electrically driven cars or trains. It willfurther be understood that the rail heating units 10 are designed to belocated at spaced intervals along the track, particularly at pointswhere the formation or the accumulation of ice, sleet or snow wouldentail more or less serious consequences.

The heating unit 10 essentially comprises an electrical resistanceelement 11 which is supported upon the inner surface of a main casing orhousing 12. As appears quite clearly in Figures 1 and 2 this housing 12,which is preferably in the form of a sheet metal stamping, is providedwith an inclined wall or plate 13 the upper and lower longitudinallyextending edges of which are flanged, as at 14 and 15. The side edges ofthe housing plate 13 are respectively inturned to provide a pair ofsubstantially parallel, triangularly shaped side walls 16. Thesetriangular side walls 16 are so shaped that when the bottom edges 1'?thereof rest upon the upper surface of the base flange of the rail thevertical edges 18 thereof will abut the web of the rail. The main backplate 13 of the sheet metal housing lies in a plane substantiallysubtending the free edges of the triangular side walls thereof, as mostclearly appears in Figure 2. When the housing is applied to the rail anenclosed space or chamber is formed therebetween, this space beingbounded at its outer side by the inclined back plate 13, at its sides bythe triangular side walls 16, at its bottom by the base flange of therail and at its inner side by the web of the rail. The heating element11 is supported upon the inclined back plate in the manner to bedescribed more fully hereinafter and in spaced relation with respect tothe enclosed portions of the rail.

In order to most effectively concentrate the heat and to direct itagainst the rail with a minimum loss in heat transmission the main backplate 13 of the housing or casing is provided with a lining 19 ofsuitable heat resisting material. As appears most clearly in Figures 2,3 and 5 this heat insulating lining 19 is maintained in position bymeans of a pair of angle members 20 riveted or otherwise secured to theside walls 16 of the casing.

Integrally formed in the inclined plate 13 of the housing or casing atlongitudinally spaced points thereof are a pair of outwardly pressedportions 20 providing a pair of sockets the axes of which lie in a planeoutwardly offset with relation to but paralleling that of the inclinedplate. The upper end of these socketed portions 20 are curved as at 21(see Figure 3) to merge into the plane of the inclined back plate 13while the lower ends of the said socketed portions 20 are open forreception of the conductor plugs 22. These plugs 22, which areelectrically connected to the ends of conductors 23 for supplyingcurrent to the resistance element, are preferably in the form of femaleelements adapted for cooperation with the male terminal elements 24 ofthe heating unit, these male terminal elements being respectivelyenclosed within the upper ends of the socketed portions 20 in the mannerto be now described.

As appears most clearly in Figure 3 the terminal elements 24 of theheating unit comprise an insulating body 25 which is adapted to benested within the upper closed end of the socketed portions 20. Theseinsulating bodies 25 are each provided with a rearwardly extendingportion 26 projecting through a suitable aperture 27 formed in the heatinsulating lining 19. The insulating bodies 25, which are ofsubstantially angular form in vertical section, are respectivelydesigned to insulatingly enclose the central body portions of theelectrical conducting members 28. These latter members are each ofsubstantially right angle form, one branch of which extends axially ofthe socket portion 20 and terminates in a freely projecting pin 29arranged for electrical engagement within the female terminal member ofthe conductor plug 22. The other branch of the conductor member 28extends axially through the rearwardly extending portion 26 of theinsulating body 25 and terminates in a freely extending threaded portion30.

Angle members 31 of the character shown most clearly in Figure 5 aresecured to the threaded ends of the terminal members 28 by means of nuts32, these angle members being so respectively secured in position thatthe branches 33 thereof are arranged in substantial parallelism andbetween which is supported the resistance element 11.

This resistance element 11 essentially comprises a tubular member 34 ofrefractory material about the external surface of which the resistancewire 35 is spirally wound. Arranged at either end of the tubular member34 is a spool 36 of non-conducting material and of a diameter greaterthan that of the tubular member 34. The latter member and the end spools36 are maintained in assembled relation by means of a metal tube 37 theopposite ends of which are respectively secured, as at 38, to the spools36. This ecurement is preferably accomplished by spinning or otherwiseforcing the ends of the metal tube 37 into annular grooves respectivelyformed in the spools 36. The space formed between the inner refractorytube 34 and the outer metal tube 37 is preferably filled with insulatingmaterial 39.

In order to effect the necessary electrical connection between the endsof the resistance wire 35 and the angle brackets 31, which latter are inelectrical engagement with the male terminal elements 28 of the heaterunit and at the same time afford a substantial mechanical joint betweenthe insulating tube 34 and its supporting end spools 36, thearrangements shown more particularly in Figures 8 and 10 are employed.In the form shown in Figure 8, end studs 40 are employed, these studsbeing each characterized by the provision of a threaded shank 41 and anenlarged head 42 of substantially rectangular cross section, the spool36 being provided in its inner surface with a rectangularly shapedsocket for partially accommodating said rectangular head 42. Theadjoining end of the tubular member 34 is diametrically slotted, as at43, for nonrotatably receiving that portion of the stud head 42 whichprojects interiorly of the end spool. With the head 42 of the stud thuscommonly accommodated within the socket portion of the end spool and theslotted portion of the tubular member 34, relative rotation between saidspool and member is effectually precluded. The head 42 of the stud issuitably apertured, as at 44, to permit the projection therethrough ofone end of the resistance wire 35, said wire being suitably brazed orotherwise permanently secured to said head to effect a positiveelectrical connection therebetween. The threaded shanks 41 of the studsextend through axial bores respectively provided in the end spools 36,the exteriorly projecting portions of these threaded shanks 41 beingadapted for projection through suitable apertures formed in the lowerends of the portions 33 of the supporting brackets 31. Nuts 45,threadedly engageable with the shanks 41, serve to maintain theresistance unit in the position shown most clearly in Figure 5.

Figures 10 and 11 show an alternative arrangement for preventingrelative rotation between the tubular member 34 and the end spools 36.

In this modified construction studs 46 are em ployed which differ fromthe studs 40 of Figure 8 in that they are each provided with an axialextension 47 adapted for projection into the bore of the tubular member34. This axial extension 47 is anchored within the end of the tube 34 bymeans of a tubular pin 48 which is projected diametrically through thetube and extension. The enlarged rectangularly shaped head 49 of thestud is non-rotatably positioned within the correspondingly shapedsocket 50 formed in the end spool such that the inner surfaces of saidhead and spool are flush with one another. The ends of the resistancewire are respectively threaded through the tubular pins 48 and aresecured thereto as by brazing, soldering or otherwise whereby apermanent electrical connection is effected between each end of the wireand one of the studs 46. In all other respects the resistance unit ofthe form shown in Figure 10 is similar to that shown in Figure 8, bothforms being removably supported between the bracket members 31 in themanner appearing most clearly in Figure 5.

It will thus be seen that the opposite ends of the resistance Wire arerespectively connected to the male terminal elements 28 of the heatingunit through the intervention of the end studs and the supportingbrackets. Due to the angular form of the terminal elements 28 and thefact that the extremities thereof project axially of the socketedportions 20 of the heater casing, the ease with which the conductors maybe connected to the unit is greatly facilitated. As was describedhereinbefore, these conductors are each provided with a plug 22 adaptedto be snugly received within the socketed portions 20.. These plugs 22are each provided adjacent the outer ends thereof with an annular groove51 which is adapted to receive a spring-pressed finger 52 for preventingaccidental or unintentional displacement of the plug from within itssocket.

The spring-pressed fingers 52 are preferably formed as integral parts ofa plate member 53 interposed between the back plate 13 of the heaterunit and the insulating-lining plate 19. As ap pears most clearly inFigures 2, 3 and '7 the struckout fingers 52 are arcuately shaped intransverse cross-section and are so disposed that they respectivelyconstitute the bottom walls of the inclined plug sockets 20. The freeextremities of the spring-pressed fingers 52 are each beaded, as at 54,to provide a detent or the like for engagement with the groove 51 of theconductor plug when the latter is inserted into position.

It will be understood, of course, that any suitable means may beprovided to maintain the heater unit in the operative position shown inFigures 1 and 2. It has been found preferable, however, to employ aspring clamp 55 having a flat body or plate 56 which is adapted tounderlie the base flange of the rail and a spring-pressed pivoted member'7 adapted to overlie the inclined back plate 13 of the heater. Theplate 56 of this clamp is preferably provided at opposite ends thereofwith upstanding flanges 58 and 59 for respectively engaging oppositeedges of the rail base flange. The central portion of the flange 59 isrolled, as at 60, to provide a bearing for a horizontally extendingsleeve 61 within the opposite ends of which are inserted the free lowerends of the bail member 57, this latter being preferably in the form ofa rod bent into the shape shown most clearly in Figure l. Embracing theoppositely projecting portions of the sleeve 61 is a coil spring 62which is operative to constantly urge the upper portion of the bailmember 57 toward and against the plate 13 of the heater unit, therebydefinitely forcing the latter into the angle formed between the base andweb of the rail.

The use of a spring clamp of the character just described eliminates thenecessity of employing screws or bolts for securing the heater to therail at the same time that it greatly facilitates the ease with whichthe unit may be secured to and removed from the rail. Should it bedesired to remove the unit from the rail for purposes of inspection,replacement or repair it is merely necessary to pull the plugs fromtheir sockets and then swing the bail member 57 outwardly about thesleeve 61 as an axis whereupon the unit may be bodily removed from therail, no tools of any sort being required in this operation.

In certain instances the base flange of the rail may vary from thestandard and accordingly it may be desirable to employ a spring clamphaving an adjustable base plate as shown in Figures 12 to 15. In theform of clamp shown in Figures 12 and 13 the base plate is formed of twomembers 63 and 64, the member 64 being provided with a spring-pressedbail member 65 similar in design and function to the hereinbeforedescribed member 5'7. The inner portions of the members 63 and 64 areadapted to be arranged in the superposed relation shown, the side edgesof these portions being respectively kerfed to provide a plurality ofalternately arranged tongues 66 and slots 67. These tongues are allinclined with respect to the planes of their respective body members andare relatively so arranged that the tongues of member 63 interlock withthe tongues of member 64 when said members are assembled in the relationshown. Obviously, the distance between the outer ends of the members 63and 64 may be varied within wide limits to accommodate base flanges ofdifferent widths merely by changing the interlocking relation betweenthe kerfed portions of the members.

In Figures 14 and 15 an alternative arrangement is shown wherein themember 68 of the spring clamp is provided in opposite sides thereof witha plurality of longitudinally spaced slots 69, the member 70 beingprovided in turn with a pair of laterally spaced downwardly presentinglugs '71 adapted to be projected through any desired set of slots 69. Inthis alternative arrangement, it is preferable, when the members 68and-'70 are assembled in properly adjusted relation, to bend the lugs 71upwardly against the bottom surface of the slotted member whereby tomore positively lock the members 68 and '70 together.

Returning again to the resistance unit per se, it will be observed thatthe end studs thereof are longitudinally bored, as at 72, to provide acontinuous passage extending longitudinally through the resistance unit.This passage permits of a circulation of heated air outwardly from thecenter of said unit to supplement the heat radiated from the externalsurface thereof.

The resistance unit and the clamp form the subject matters ofapplications Serial Numbers 626,573 and 626,574, respectively.

It will be understood of course that the invention is susceptible ofvarious changes and modifications other than those hereinbefore pointedout, all without departing from the general principles or real spirit ofthe invention, and it is accordingly intended to claim the same broadly,

as well as specifically, as indicated by the appended claim.

What is claimed as new and useful is:-- In an electric heater, incombination, a protec- 5 tive casing for an electric heating unitcomprising a. main back wall having an outwardly pressed portionconstituting a socket for a. conductor plug, a heat insulating liningfor said back wall, and a plate interposed between said lining and saidwall and having means projecting interiorly of said outwardly pressedportion for frictionally engaging a conductor plug inserted Within saidsocket.

WILLIAM H. GREENFLELD.

